I have a 2011 Macbook Pro with a 10.6.8 and 10.11.6 partitions and want to add a 3rd one for 10.15 (via dosdude patcher) but need to update the firmware to support the APFS file system first. I need to know with 100% certainty that I will still be able to boot into 10.6.8 & 10.11.6 after installing the High Sierra 10.14 firmware update as I spend most of my time running legacy software on the 10.6.8 osx.

  • High Sierra is 10.13.
    – lhf
    Sep 12, 2021 at 12:03

1 Answer 1


The firmware update included with High Sierra include drivers to allow the firmware to access ExFAT and APFS volumes. The existing drivers for FAT32 and HFS are preserved. When I upgraded my 2011 iMac to High Sierra, the partition where High Sierra was installed was not automatically converted to APFS since the partition was on an internal HDD. (Conversion only occurs automatically if installing to a SSD.) Therefore, the Mac is still booting macOS 10.13.6 from a JHFS+ formatted partition. So I can confirm the ability to boot from legacy HFS partitions is preserved after installing High Sierra.

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